Backrest assembly

ABSTRACT

A bracket assembly includes a backrest, a support and a fastener. The backrest defines a hole with a wall formed with a thread. The support is attached to a seat and defines a slot. The fastener includes a bolt formed with a thread and a head secured to the bolt. The bolt is inserted through the slot and the thread formed on the bolt is engaged with the thread formed on the wall of the hole in order to sandwich the support between the backrest and the head so as retain the backrest in position on the support. The engagement the thread formed on the bolt with the thread formed on the wall of the hole can be loosened so as allow adjustment of the position of the backrest on the support. In another aspect, the backrest includes a first panel and a second panel. The first panel defines a hole with a wall on which a thread is formed and a second panel. The second panel defines a hole. The support is located between the first panel and the second panel. The bolt is inserted through the hole defined in the second panel and the slot. The thread formed on the bolt is engaged with the thread formed on the wall of the hole defined in the first panel in order to sandwich the support between the first panel and the second panel so as retain the backrest in position on the support.

BACKGROUND OF INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to a backrest assembly.

[0003] 2. Related Prior Art

[0004] Taiwan Patent Publication No. 148172 discloses a backrest-elevating device. This conventional device is arranged between a seat and a backrest 4. A cavity 12 is defined within a frame-shaped portion formed on a rear face of the backrest 4. This conventional device includes a support 2 connected with the seat. A slot 21 is defined in the support 2. The slot 21 includes several enlarged portions. A first mount 22 is flat in configuration. A hole is defined in the first mount 22. A second mount 23 includes a central portion and two terminal portions extend in a different plane than a plane in which the central portion extends. A hole 24 is defined in the central portion of the second mount 23. When assembled, the first mount 22 and the second mount 23 define a space for receiving the support 2. The pin 25 includes a central portion, an enlarged terminal portion formed as a head 251 and a reduced terminal portion in which a groove 26 is defined. In assembly, the pin 25 is inserted in the hole defined in the first mount 22, the slot 21 and the hole 24. The head 251 is received in the hole defined in the first mount 22 and one of the enlarged portions of the slot 21. The central portion of the pin 25 is inserted through the hole 24. The groove 26 is positioned beyond the second mount 23. A spring 27 is mounted on the central portion of the pin 25. A C-clip 28 is received in the groove 26 so that the spring 27 is compressed between the second mount 23 and the C-clip 28. A button 3 is mounted on the reduced terminal portion of the pin 25. The first mount 22 and the second mount 23 are secured to the frame-shaped portion of the backrest 4. In use, the head 251 is normally received in one of the enlarged portions of the slot 21 so as to retain the position of the backrest 4 on the post 2. A user can press the button 3 so as to remove the head 251 from the one of the enlarged portions of the slot 21 in order to allow adjustment of the position of the backrest 4 on the support 2. This conventional device is extremely complicated in structure for including a lot of components. Furthermore, the number of the holes 41 limits the number of the positions available for the backrest 4.

[0005] Taiwanese Patent Publication No. 480961 discloses a chair with a simple mechanism for adjusting the elevation of a backrest. This conventional chair includes a base 2, a seat 3 mounted on the base 2, a support 4 connected with the seat 3, an adjusting device 5 movably mounted on the support 4 and a backrest 6 connected with the adjusting device 5. The support 4 includes a plurality of holes 41 defined therein along a length (or height) thereof. The adjusting device 5 includes a mount 51 with a central portion and two terminal portions extend from the central portion at an angle. The terminal portions of the mount 51 are secured to the backrest 6. A space 511 is defined by means of the mount 51 and the backrest 6. A hole 518 is defined in the central portion of the mount 51. A lever 52 is pivotally mounted on the central portion of the mount 51. The lever 52 includes an insert 521 formed at an end and a button 522 mounted on an opposite end. Normally, the insert 521 is inserted in one of the holes 41 through the hole 518 so as to retain the backrest 6 in one of several positions on the support 4. A user can press the button 522 so as to remove the insert 521 from the one of the holes 41 in order to allow adjustment of the position of the backrest 6 on the support 4. This conventional chair is complicated in structure for including quite a few components. Furthermore, the number of the holes 41 limits the number of the positions available for the backrest 4.

[0006] The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.

SUMMARY OF INVENTION

[0007] It is an objective of the present invention to provide a backrest-positioning device that is simple in structure.

[0008] It is another objective of the present invention to provide a backrest-positioning device that provides an indefinite number of positions.

[0009] According to the present invention, a bracket assembly includes a backrest, a support and a fastener. The backrest defines a hole with a wall formed with a thread. The support is attached to a seat and defines a slot. The fastener includes a bolt formed with a thread and a head secured to the bolt. The bolt is inserted through the slot and the thread formed on the bolt is engaged with the thread formed on the wall of the hole in order to sandwich the support between the backrest and the head so as retain the backrest in position on the support. The engagement the thread formed on the bolt with the thread formed on the wall of the hole can be loosened so as allow adjustment of the position of the backrest on the support.

[0010] In another aspect, the backrest includes a first panel and a second panel. The first panel defines a hole with a wall on which a thread is formed and a second panel. The second panel defines a hole. The support is located between the first panel and the second panel. The bolt is inserted through the hole defined in the second panel and the slot. The thread formed on the bolt is engaged with the thread formed on the wall of the hole defined in the first panel in order to sandwich the support between the first panel and the second panel so as retain the backrest in position on the support.

[0011] Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the attached drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0012] The present invention will be described through detailed illustration of embodiments referring to the attached drawings.

[0013]FIG. 1 is a perspective view of a backrest assembly according to a first embodiment of the present invention.

[0014]FIG. 2 is an exploded view of the backrest assembly.

[0015]FIG. 3 is a cross-sectional view of the backrest assembly, showing a backrest in a lower position on a support.

[0016]FIG. 4 is a cross-sectional view of the backrest assembly.

[0017]FIG. 5 is a cross-sectional view of the backrest assembly, showing the backrest in an upper position on the support.

[0018]FIG. 6 is an exploded view of a backrest assembly according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0019] Referring to FIGS. 1 and 2, according to a first embodiment of the present invention, a chair includes a base 2, a seat 1 mounted on the base 2, a support 10 connected with the seat 1 or the base 2, a backrest 3 and a backrest-positioning device 4 arranged between the support 10 and the backrest 3.

[0020] The support 10 is a tube including two slots 11 each defined in one of two opposite faces thereof.

[0021] The backrest 3 includes a first panel 31 and a second panel 32. The first panel 31 includes a first face 311 and a second face 312. A soft pad (not shown) can be mounted on the first face 311 of the first panel 31 in order to provide comfort for a user. Two ridges 313 are formed on the second face 312 of the first panel 31. A space 314 is defined between the ridges 313 in order to receive the support 10. A hole 315 is defined in the second face 312 of the first panel 31. The hole 315 is located between the ridges 313. A thread is formed on the wall of the hole 315. Four bosses 316 are formed on the second face 312 of the first panel 31.

[0022] The second panel 32 includes a first face 321 and a second face 322. A recess 326 is defined in the second face 322 of the second panel 32. A hole 325 is defined in the second panel 32. The hole 325 is co-axial with the recess 326, i.e., they make a so-called countersink hole. Four recesses 323 are defined in the first face 321 of the second panel 32.

[0023] A fastener 4 includes knob 41, a hub 42 formed on the knob 41 and a bolt 43 with a first end fit in the hub 42 and a second end formed with a thread. The knob 41 is used to facilitate rotation of the bolt 43.

[0024] In assembly, the support 10 is received in the space 314. The slots 11 are aligned with the hole 315. The second panel 32 is located beside the first panel 31. The bosses 316 are received in the recesses 323 for alignment of the first panel 31 with the second panel 32. The hole 325 is aligned with the slots 11 and the hole 315. The bolt 43 is inserted through a washer 44, the hole 325 and the slots 11 into the hole 315. The thread formed on the bolt 43 is engaged with the thread formed on the wall of the hole 315.

[0025] Referring to FIG. 3, the thread formed on the bolt 43 is tightly engaged with the thread formed on the wall of the hole 315. Thus, the hub 42 pushes the washer 44 that in turn pushes the second panel 32 so as to sandwich the support 10 between the first panel 31 and the second panel 32. Therefore, the backrest 3 is retained in position on the support 10.

[0026] Referring to FIG. 4, the engagement of the thread formed on the bolt 43 with the thread formed on the wall of the hole 315 is loosened so as allow the second panel 32 to move from the support 10 due to elasticity of the second panel 32. The support 10 is no longer sandwiched between the first panel 31 and the second panel 32. Hence, the position of the backrest 3 on the support 10 can be adjusted arbitrarily provided that the bolt 43 is received in the slots 11.

[0027] Referring to FIG. 5, the backrest 3 is moved to an upper position on the support 10. The engagement of the thread formed on the bolt 43 with the thread formed on the wall of the hole 315 is tightened. Thus, the support 10 is sandwiched between the first panel 31 and the second panel 32. Therefore, the backrest 3 is retained in the upper position on the support 10.

[0028]FIG. 6 shows a backrest assembly according to a second embodiment of the present invention. The second embodiment is identical to the first embodiment except for including a solid support 10 instead of a hollow support 10. Accordingly, only one slot 11 is defined instead of two slots 11.

[0029] The present invention has been described through detailed illustration of the preferred embodiments. Those skilled in the art can derive many variations from the preferred embodiments without departing from the scope of the present invention. Therefore, the preferred embodiments shall not limit the scope of the present invention defined in the attached claims. 

1. A backrest assembly including: a backrest defining a hole with a wall formed with a thread; a support defining a slot and being attached to a seat; a fastener including a bolt formed with a thread and a head secured to the bolt, wherein the bolt is inserted through the slot and the thread formed on the bolt is engaged with the thread formed on the wall of the hole in order to sandwich the support between the backrest and the head so as retain the backrest in position on the support, and the engagement the thread formed on the bolt with the thread formed on the wall of the hole can be loosened so as allow adjustment of the position of the backrest on the support.
 2. The backrest assembly according to claim 1 wherein the support is a tube.
 3. The backrest assembly according to claim 1 wherein the support is a strip.
 4. The backrest assembly according to claim 1 wherein the backrest includes two ridges formed thereon, and the support is located between the ridges so as to restrain rotation of the backrest on the support.
 5. The backrest assembly according to claim 1 wherein the fastener includes a knob secured to the head in order to facilitate rotation of the bolt.
 6. A backrest assembly including: a backrest including a first panel defining a hole with a wall formed with a thread and a second panel defining a hole; a support including a first section attached to a seat and a second section defining a slot and being located between the first panel and the second panel; a fastener including a bolt formed with a thread and a head secured to the bolt, wherein the bolt is inserted through the hole defined in the second panel and the slot, and the thread formed on the bolt is engaged with the thread formed on the wall of the hole defined in the first panel in order to sandwich the support between the first panel and the second panel so as retain the backrest in position on the support, and the engagement the thread formed on the bolt with the thread formed on the wall of the hole can be loosened so as allow adjustment of the position of the backrest on the support.
 7. The backrest assembly according to claim 6 wherein the support is a tube.
 8. The backrest assembly according to claim 6 wherein the support is a strip.
 9. The backrest assembly according to claim 6 wherein the first panel includes two ridges formed thereon, and the support is located between the ridges so as to restrain rotation of the first panel on the support.
 10. The backrest assembly according to claim 6 wherein one of the first and second panels includes a plurality of bosses and the remaining one of the first and second panels defines a corresponding number of recesses for receiving the bosses in order to align the first pane with the second panel.
 11. The backrest assembly according to claim 6 wherein the fastener includes a knob secured to the head in order to facilitate rotation of the bolt. 